Author: Darcy Ross
Institution: University of Illinois Urbana - Champaign
Date: November 2010
A recent discovery by Yale scientists has shed new light on the RNA world theory, which proposes that RNA molecules once performed the roles of both protein and DNA as the basis of life. In the August 13 issue of Science, an RNA complex was found regulating gene expression within Clostridium difficile, a normal flora bacterium in the body. This was once thought to be a task only performed by proteins.
There has long been a "chicken-and-the-egg" controversy regarding DNA and proteins, the current basis of life. The RNA world theory could potentially solve this dilemma since RNA molecules can store information (they are the templates for protein production) like DNA and also have some enzymatic activity like proteins.
Ron Breaker, the lead scientist of this project, and his associates have in fact discovered a whole class of these so-called "riboswitches". These are RNA molecules that can act as sensors and subsequently regulate gene expression.
Breaker explained in an interview with Science News: "A lot of sophisticated RNA gadgetry has gone extinct but this study shows that RNA has more of the power needed to carry out complex biochemistry. It makes the spontaneous emergence of life on earth much more palatable."
This discovery lends much credibility to the RNA world theory and may entirely overturn the common teaching (Figure 1) that RNA molecules are relatively one-dimensional molecules suitable only as an intermediate between DNA and proteins.
Author: Darcy Ross
Reviewed by: Mai Truong and Yangguang Ou
Published by: Maria Huang